package com.tanhua.server.interceptor;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.tanhua.common.utils.Cache;
import org.apache.commons.codec.digest.DigestUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@Component
public class RedisCacheInterceptor implements HandlerInterceptor {
    @Value("${tanhua.cache.enable}")
    private Boolean enable;
    @Autowired
    private RedisTemplate<String,String> redisTemplate;

    private static final ObjectMapper MAPPER=new ObjectMapper();
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        if(!enable){
            return true;
        }
        if(!(handler instanceof HandlerMethod)){
            return true;
        }
        if (!((HandlerMethod) handler).hasMethodAnnotation(GetMapping.class)){
            return true;
        }
        if(!((HandlerMethod) handler).hasMethodAnnotation(Cache.class)){
            return true;
        }
        //生成独有的redisKey
        String redisKey=createRedisKey(request);
        String cacheData = this.redisTemplate.opsForValue().get(redisKey);
        if (null==cacheData) {
            return true;
        }
        System.out.println("拦截器释放数据");
        response.setCharacterEncoding("UTF-8");
        response.setContentType("application/json;charset=UTF-8");
        response.getWriter().write(cacheData);
        return false;
    }

    public static String createRedisKey(HttpServletRequest request) throws Exception {
        String token=request.getHeader("Authorization");
        String url = request.getRequestURI();
        String param = MAPPER.writeValueAsString(request.getParameterMap());

        String data=url+"_"+param+"_"+token;
        return "SERVER_CACHE_DATA_"+ DigestUtils.md5Hex(data);
    }


}
